Microbiology Department, Consorcio Hospital General Universitario de Valencia, Valencia, Spain.
Microbiology and Ecology Department, University of Valencia, Burjassot, Spain.
Mycoses. 2021 Jun;64(6):612-615. doi: 10.1111/myc.13250. Epub 2021 Feb 9.
Rapid and reliable laboratory methods are required for detecting the nosocomial yeast Candida auris. AurisID (Olm Diagnostics) is a real-time PCR assay approved for detecting C. auris in fungal cultures and directly from blood samples, involving a nucleic acid extraction as a prior step.
The purpose of this study is to validate the AurisID kit for direct detection of C. auris from surveillance samples without prior DNA extraction and to analyse the results of implementing this methodology to our daily laboratory routine protocol for C. auris surveillance studies.
Our PCR method using the AurisID kit was compared with our routine protocol, consisting of culture in CHROMagar Candida and identification by mass spectrometry. A total of 113 swabs were used for validation and 136 pair of surveillance samples were tested. Limit of detection (LOD) was determined by using swabs in Amies transport medium, which were spiked in a series of dilutions of a C. auris standardised suspension (0.5 McFarland).
The PCR method showed high sensitivity, specificity, predictive positive value and predictive negative value (96.6%, 100%, 100% and 98.2%, respectively) when compared with the routine protocol. LOD was 500 CFU/ml, which corresponds to approximately 1 CFU/PCR.
Our PCR method using the AurisID kit allows a reduction in the turnaround time for surveillance of C. auris compared with other methods. These results are expected to contribute to control C. auris outbreaks, allowing isolation of patients and cleaning of environmental surfaces in advance.
需要快速可靠的实验室方法来检测医院酵母假丝酵母菌。AurisID（Olm Diagnostics）是一种实时 PCR 检测方法，已批准用于检测真菌培养物和直接从血液样本中的假丝酵母菌，涉及核酸提取作为前一步。
本研究旨在验证 AurisID 试剂盒用于直接检测无需预先 DNA 提取的监测样本中的假丝酵母菌，并分析实施该方法学对我们日常实验室假丝酵母菌监测研究常规方案的结果。
我们使用 AurisID 试剂盒的 PCR 方法与我们的常规方案进行比较，常规方案包括在 CHROMagar Candida 上培养并通过质谱鉴定。总共使用了 113 个拭子进行验证，并测试了 136 对监测样本。通过在 Amies 运输培养基中的拭子确定检测限（LOD），该拭子系列稀释了假丝酵母菌标准悬浮液（0.5 McFarland）。
与常规方案相比，PCR 方法显示出较高的灵敏度、特异性、预测阳性值和预测阴性值（分别为 96.6%、100%、100%和 98.2%）。LOD 为 500 CFU/ml，相当于约 1 CFU/PCR。
与其他方法相比，我们使用 AurisID 试剂盒的 PCR 方法可缩短假丝酵母菌监测的周转时间。这些结果有望有助于控制假丝酵母菌的爆发，提前隔离患者并清洁环境表面。
